Finding the Fourth Proportional to 1,223.37, 1,688.28 and 699.39

Step by Step Solution

1. Step 1: Write the proportion equation
   1,223.37 : 1,688.28 = 699.39 : x
2. Step 2: Convert to fraction form
   1,223.37/1,688.28 = 699.39/x
3. Step 3: Cross multiply
   1,223.37x = 1,688.28 × 699.39
4. Step 4: Simplify right side
   1,223.37x = 1,180,766.15
5. Step 5: Solve for x
   x = 1,180,766.15/1,223.37
6. Step 6: Final answer
   x = 965.18